The use of ophthalmic lenses, such as contact lenses, for the correction of ametropia is well known. A number of methods for designing contact lenses also are known. Typically, these methods involve one or more of benchmarking of known designs, developing theoretical target values for control optical parameters, obtaining subjective patient feedback, and using objective testing methods to produce a lens design. One disadvantage of these design methods is that they do not accurately take into account the effect of on-eye movement of the lens or the effect of eyelid movement on lens stability.
Additionally, for correction of certain optical defects, non-spherical corrective characteristics must be designed into one or more surfaces of the contact lens such as cylindrical, bifocal, or multifocal characteristics. However, the design of these lenses is problematic in that the lens must be designed to perform so as to quickly attain and then maintain a specific orientation while on the eye to be effective. Evaluating performance of the lens designs that incorporate non-spherical correction requires many iterations during which the lens is tested on-eye, feedback from the lens wearer is used to optimize the lens design, and the lens is re-tested on-eye, resulting in a lens design and evaluation cycle that is lengthy.